A huge market exists for disk drives for mass-market computing devices such as desktop computers and laptop computers, as well as small form factor (SFF) disk drives for use in mobile computing devices (e.g. personal digital assistants (PDAs), cell-phones, digital cameras, etc.). To be competitive, a disk drive should be relatively inexpensive and provide substantial capacity, rapid access to data, and reliable performance.
One example of a disk drive is a hard disk drive. A conventional hard disk drive includes a rotating magnetic disk, write and read heads that are suspended by a suspension arm adjacent to a surface of the rotating magnetic disk, and an actuator that swings the suspension arm to place the read and write heads over selected circular tracks on the rotating disk. The read and write heads are directly located on a slider that has an air bearing surface (ABS). The suspension arm biases the slider towards the surface of the disk, and when the disk rotates, air adjacent to the disk moves along with the surface of the disk. The slider flies over the surface of the disk on a cushion of the moving air.
When the slider rides on the air bearing, the write and read heads are employed for writing magnetic transitions to and reading magnetic transitions from the rotating disk. The read and write heads are connected to processing circuitry that operates according to a program to implement writing and reading functions.
Perpendicular magnetic recording (PMR) transducers are now being utilized to increase the data density of hard disk drives. Such perpendicular magnetic recording transducers record magnetic bits of a data in a direction that is perpendicular to the surface of the magnetic disk. A write head is used that generally includes a write pole having a relatively small cross section at the air bearing surface (ABS) and a return pole having a larger cross section at the ABS. A magnetic write coil induces a magnetic flux to be emitted from the write pole in a direction generally perpendicular to the plane of the magnetic disk.
Thus, a conventional magnetic recording head may include a PMR transducer residing on the slider. As previously described, the slider also includes an air-bearing surface (ABS) that faces the disk. A conventional PMR transducer may include a PMR pole and a top shield separated by a write gap. The top shield may also act as a pole during writing. The conventional PMR pole may be surrounded by an insulating layer. Similarly, the top shield may also be surrounded by another insulating layer.
The conventional PMR pole may have sidewalls. In some applications, the height of the conventional PMR pole may be less than approximately three-tenths micrometer. The conventional PMR pole may also have a negative angle such that the top of the conventional PMR pole is wider than the bottom of the conventional PMR pole. Stated differently, the angle of the sidewalls may be less than 90 degrees. A pole having this height and shape is desirable for use in PMR applications.
However, in the case of conventional PMR pole fabrication, when a reactive ion etching (RIE) process is used in an insulating layer, an undesirable sidewall angle difference between the yoke and trench occurs due to an inevitable RIE loading effect caused by the different etching area between the trench area and the yoke area. Unfortunately, because of the sidewall angle difference between the yoke area and the trench area, the overall writing performance of the PMR pole of the write head is decreased.
Accordingly, there is a need for an improved PMR pole fabrication method in which the sidewalls of both the yoke area and trench area are formed having similar sidewall slopes.